A large proportion of healthy African Americans have been observed to have a white blood cell count (WBC) that is persistently lower than the normal range defined for individuals of European ancestry [1]â[5].
Energy is only released when chemical bonds are formed. In general, a chemical reaction involves two steps: 1) the original chemical bonds between the atoms are broken, and 2) new bonds are formed. These two steps are sometimes lumped into one event for simplicity, but they are really two separate events.
Exothermic and endothermic reactions both cause some type of energy level differences. In an exothermic reaction, energy is released in the form of heat. As chemical bonds are formed, energy is released. An example is water turning into ice. Chemical bonds form and release energy to create ice crystals. An endothermic reaction, however, is the opposite. Here, the energy is absorbed in the form of heat. When a chemical bond is broken, the energy used creates an endothermic reaction. Changing ice into water, then vapor, requires the chemical bonds to be broken.